The delivery of information programs, such as video, entertainment, and educational programs, to large numbers of subscribers has largely been provided through a few widespread technologies. The most prevalent technology, which is familiar to most subscribers, is broadcast television. Under this delivery scheme, television networks, such as CBS, NBC, ABC, and FOX, and a host of independent broadcasters distribute pre-scheduled programs to subscribers by broadcasting at radio-frequencies through the atmosphere. Another commonplace program delivery scheme is cable television. In a typical cable television system, a variety of programs are broadcast over a physical medium (such as coaxial and optical cable), and subscribers who pay for access to the physical medium receive broadcast programs.
Satellite broadcasting is another technology used to deliver programs to subscribers. With this technology, programs are broadcast from a central location via satellite, and subscribers receive the broadcast programs using large, high-gain antennas often called "satellite dishes". To receive the programs transmitted from present-day, low-powered satellites, the subscriber must erect a rather large antenna to provide enough gain for adequate reception of broadcast programs.
An advantage of the broadcast delivery technologies described above is that the cost per subscriber is low since the cost of broadcasting programs is shared among all subscribers. In the case of broadcast television, the cost to the subscribers for access to programs is free since advertisers foot the bill. While each of these methods offers a level of convenience and usefulness, they suffer in that the delivery of video information is done in a broadcast fashion. Broadcast delivery proves to be inadequate in many cases to meet the diverse needs of subscribers for information programs. A major drawback of the broadcast delivery schemes described above is that subscribers have no direct input on the programs to be broadcast over the network. Thus, the selection and scheduling of programs is determined by the network providers and cannot be specifically catered to meet the needs of individual subscribers. Instead, subscribers must adjust their schedules around the date and time pre-set by the networks for airing particular broadcast programs.
Another major shortcoming of conventional broadcasting delivery technologies is the limited number of program choices offered to subscribers at once. Subscribers' choices are limited to those programs being broadcast at the time. Once a subscriber has flipped through the channels that are receivable within his vicinity, the available choices have been exhausted. In the case of broadcast television in most metropolitan areas, the number of program choices is limited to 6 or 7 since only 6 or 7 channels are offered simultaneously in the most commonly viewed VHF spectrum.
Another limitation of conventional technologies is that broadcast delivery is not conducive to allowing customer control of the play-out of the program. In effect, subscribers have little or no opportunity to control the play-out of the program being viewed in conformance with their special needs and purposes. Therefore, subscribers are not afforded the flexibility to fast forward during commercials, to forward past gruesome scenes, to rewind in order to have missed information instantaneously repeated, or pause during interruptions. Instead, subscribers must receive programs substantially as selected, scheduled, and transmitted by the network.
Realizing these shortcomings of conventional broadcast delivery technologies, attempts have been made to offer more flexibility to subscribers. For example, cable television networks offer some programs on a pay-per-view basis in which customers can tune to special pre-scheduled programs for an additional cost above and beyond the regular service charge. Although this added feature allows subscribers access to additional programs, subscribers still do not have the flexibility of scheduling start time and date of the program and of interactively playing out the desired program according to their own needs and desires.
Another attempt to overcome the limitations of conventional broadcast delivery technologies is the development of a video recorder/transmitter, which is capable of receiving programs in either compressed or decompressed format; one such device is described in Audio/Video Transceiver Apparatus Including Compression R. A. Lang, U.S. Pat. No. 4,963,995, Oct. 16, 1990. This device can receive programs based on accelerated delivery and permits interactive play-out of the program in real-time to the subscriber. Although this device overcomes a number of the shortcomings of conventional broadcast delivery technologies, this approach is cost-prohibitive for the average subscriber in at least one embodiment since the device would contain over a gigabit of semiconductor ram and would currently cost approximately fifty thousand dollars and may require a downstream communications channel of several hundred megabits per second (Mb/s) to be connected at the subscriber's premises.
The invention of video-cassette recorders (VCRs) has significantly obviated some of the shortcomings of conventional broadcast delivery schemes since this device allows a subscriber to record a broadcast program for later viewing at a more convenient time. Or if two programs are being broadcast simultaneously on different broadcast channels, a subscriber can watch one program and record the other for viewing later. Although the VCR obviates scheduling constraints of conventional broadcast delivery technologies and gives subscribers the flexibility to interactively play programs at their convenience, this device alone has not resolved the drawback of limited program options available to subscribers.
Video rental stores which offer movies, educational material, games, and other types of information programs have sprung up to meet the subscribers' demands for more program options. In exchange for a greater variety in program choices, a subscriber must endure the inconvenience of picking up the program from the video rental store and returning it by a certain date and time.
In view of the shortcomings of conventional broadcast technologies and ineffective strategies to obviate these shortcomings, it is the object of our invention to: 1) accommodate subscribers' diverse needs for information programs from a variety of sources; 2) allow subscribers the flexibility to access programs on demand to fit their individual preferences and schedules; 3) provide subscribers with interactive play-out capabilities; 4) allow access to interactive multi-media applications such as video games, home shopping, home banking, etc; and 5) provide an architecture which provides maximal sharing of the information providers storage resources and the network resources.